<正>通过研究３种水生植物在两个不同的生态水平上对重金属铅和锌的生态效应，发现水生植物对有害环境因子的生态敏感度，在植物个体水平上与在分子水平上的表现截然相反。按照植物体内过氧化氨酶Ｃａｔａｌａｓｅ（ＣＡＴ）的活性将３种植物的ＣＡＴ敏感度排序，则：水花生＞紫背萍＞马来眼子菜。这一结论与植物形态伤害症状所表现出的生态敏感度（种敏感度）顺序相反（马来眼子菜＞紫背萍＞水花生），说明生态敏感度概念在不同的生态水平上有不同的意义。

By measuring the CAT activities of aquatic plants exposed to heavy metals of Pb and Zn, the experimental results show that the order for the CAT sensitivities of three plant species is: Alternanthera philoxeroides> Spirodela polyrrhiza > Potamogeton malaianus. It is contrary to the results of ecological sensitivities showed by three plant species with tissue injured, such as: Potamogeton malaianus > ,Spirodela polyrrhiza > Alternanthera philoxeroides. It is said that the signification about ecological sensitivity is different between both ecological levels of organizm and molecule.